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Yes, there would be a handling improvement using that set up as it is a big step up on wheel rates from original and is in the upper range of what a lot of "pro-touring" type cars are running. However, you don't realize the full potential of the changes when the uni-body structure starts flexing. When your putting suspension loads that are this big of an increase, your body is going to be moving around. Similarly, once the body becomes an active participant in the suspension motion, handling can become unpredictable as you expose each new weak area. Check out the XV video on chassis movement and you'll be surprised how much these things move in their stock form. While it is unlikely that your car would just come apart, over time it is possible that you would begin to pop spot welds here and there and as each weld yields, you increase the load on remaining points. That could eventually lead to buckling or tearing an exterior panel. My guess would be the first place to start showing fatigue would be seams where the roof attaches.

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I've got over 50K miles on .99" 185 lbs/in rate torsion bars, KYB or performnace shocks, 60 or 50 series tires,... and no sub frame connectors.

I've seen lots of regular stock mopars separate the weld at the firewall to the floorboard. That spot welded pinch seam on top of the bell housing area. My 383 Auto Challenger showed signs of pulling there. And my Cuda with .99 T-bar is starting to show signs too. Both cars are So Cal no rust cars.

Also on A-bodies the ends of the shock towers to the frame rail will crack. My 68 conv dart, my 68 Cuda, and I check A-bodies over the years in the junks yards and spotted that. Again none of those cars had any rust in that area or anywhere structural.

Now I traveled 1600 miles across country with my 68 Cuda loaded to 5600 lbs without any front bumpstops. I didn't re-adjust ride height adjustment screws. So, the frame was hitting metal to metal on bumps during the trip. Right after that, the torsion bar hole on the K-member broke it's welds. And the frame showed some cracks around the K-member nuts that are welded to the underside of the frame.

Since that happened in 1997 I still run it without bumpstops. I haven't had any issues. I'm sure the chassis flexes.

Sure someday I would like to put in frame connectors. I just need to save up for the expensive of buying them and installing them.

Mitch Lelito SCCA Autocrossed a 70 Challegner T/A from early 70's to early 2000's with 1.24" T-bars and SUPER stiff suspension and tires. He has no frame connectors (not allowed in rules until very recently). Now that they are allowed I'm sure he'd like to put some in.

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You guys with track time seldom mention two things that make a huge difference on how a car actually gets around corners:
1. How well the driver is seated/belted in
2. And the driver's skill/experience level

Those two items will likely outweigh almost any 3 things mentioned so far except maybe the tires, ie the driver needs seat time before going off on an internet induced spending sprees.

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Absolutely.

That's why one of the reason's mine is low bucks. Also, lack of funds is big reason

Tim Werner in that 68 Valiant is a track instructor. He has lots and lots of seat time.

I've heard stories about Dick Guldstrand giving driving instructions at the old Riverside Raceway. He would take a Chevy station wagon packed elbow to elbow with students around the track. They said they thought the door skins were touching the track

More than a few times that loaded station wagon would have fastest time of the day. Later he gave lessons in a mid 70's Caprice 454 Convertible

I had a copy of this article posted on my website for years, but AOL dumped my 68 Cuda Autocrosser website. Read this written by the famous Dick Guldstrand...


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Some Handling Theory

By now you have probably read enough "straight talk" articles about high-speed handling to be totally confused. Your condition stems from the fact that most such articles are written to sell rather than to inform. This section will outline a few basic concepts, which will help you make an enlightened choice about how to modify your car for superior handling. Some parts will get a bit theoretical, but the knowledge gained will be worth the effort, so bear with us.

Where to start?
Where do we start this discussion of high-speed handling? I can tell you it doesn't start with G-forces, gumball tires, spring rates or any other thing the enthusiast considers central to high performance.

It starts with Joe Average. You've met him. He's the driver of that car acting as a moving chicane on your favorite back road. Joe is also the typical car buyer and the key to General Motor's plans for making big profits. They want to sell a large volume of cars all based on the same basic design. To do this they must appeal to the large group of buyers in the middle of the market. Sport coupes like the Z51 Corvette, Z-28 Camaro, and Trans Am Firebird represent the most that GM is willing to do for the enthusiast. If GM can't sell hundreds of thousands of a particular part over the life of a model run, they are simply not interested. Their marketing plans rely on volume.

We need to look at how Joe drives and what he expects from a car. Then we can compare his style with that of "The Enthusiast Driver". Once we understand these differences, we can look at how they affect the overall design of the car. The best way to examine these differences is by watching our two drivers negotiate a typical turn.

A Typical Turn
Let's assume a 180°, medium-speed corner with a radius of approximately 230 feet. This turn will have a total distance along its circumference of 722 feet. If you are having a hard time visualizing it, think of a 180° freeway on-ramp with a recommended speed of 25 mph. Assume also that Joe and Enthusiastic are driving base-model Coupes, which weigh about 3500 pounds. Cornering in a normal manner, Joe will round the turn at 30 mph. His subjective reaction to the cornering experience will be that the car handles just fine. Enthusiastic will corner at 45 mph. He feels that the car leans too much and is not precise.

Why do Joe and Enthusiastic have such different reactions to driving the same car around the same turn? The simple answers are that Enthusiastic is going faster than Joe or that the base-model coupe is designed for Joe's driving style rather than Enthusiastic's. While these answers are valid, they don't help us decide how to obtain superior handling. We're looking for a more fundamental understanding. To get it, we have to discuss some basic physics and the nature of human response to time-distance relationships.



It's Only Natural
The basic physics we need to examine is the concept of energy. Of particular interest is kinetic energy, the so-called energy of motion, which is present in all moving objects. The amount of kinetic energy in any particular moving object is determined by both the weight and velocity of the object. It is important to realize how weight and velocity influence the amount of energy. This relationship is expressed by the formula:

Energy =
½ Weight x Velocity²

This tells us the amount of kinetic energy increases in direct proportion to added weight and in geometric proportion with added velocity. Thus if the weight doubles the kinetic energy also doubles, but if the velocity doubles the energy will be four times greater. Let's get down to earth by seeing how much energy is involved as our two drivers round the typical turn as above. When Joe Average rounds the corner at 30 mph, he is cornering at about 0.279 g. The amount of energy involved is about 142,785 Newton-meters. Enthusiastic Driver goes around the turn at 45 mph, or about 0.628 g, which is not that slow for a base-model car. The amount of energy involved as Enthusiastic corners is about 321,183 Newton-meters. Notice that while Enthusiastic is going 50 percent faster than Joe (45 vs. 30 mph) the amount of kinetic energy involved has increased by 125 percent (321,183 vs. 142,785 Newton-meters).

You're thinking this is all very interesting but wondering how it relates to improving your car. Well, it means that the amount of energy involved with your car during cornering is the basic physical design criteria used in the construction of all suspension components. Think of the suspension components as devices to resist, store and control energy. The spring is a good example. We always hear people talking about spring rates. What does "spring rate" really mean? When we say that a spring has a rate of 250 pounds per inch, it means the spring can store 250 inch/pounds of energy for each inch of compression.

Why don't we use our example again? If we assume that as Joe goes round the turn his outside springs are compressed one inch; then as Enthusiastic Driver corners, the outside springs will be compressed an additional 1.25 inches. How does this extra compression affect the driver's subjective reaction to handling? At this point we get to the second important concept: the nature of human response to time-distance relationship.

It's Just Human
Back at our typical turn, we can watch more closely as our two drivers negotiate the corner. Recall that Joe Average went around the turn at 30 mph, or to put it another way, at 44 feet per second. Assume that as Joe enters the turn, the car takes 2 seconds to roll over, compress the outside springs and come to a steady-state cornering attitude. Likewise, at the exit of the turn, Joe's car takes about 2 seconds to unroll and get comfortably straight again. Watching Joe go through our 722 foot long turn, we see that it takes him 88 feet to transition into the turn, that he has 546 feet of steady-state cornering and another 88 feet of transition back onto the straight. Joe spends a total of 16.4 seconds in the turn.

Of these, 4 seconds (24%) are spent in difficult transitional cornering maneuvers, and 12.4 seconds (76%) are spent in relatively easy steady state cornering. This is why Joe feels that the car handles fine. At 30 mph, he spends relatively little time doing the difficult tasks of getting on and off the proper line and has a good deal of time in the middle of the turn to make corrections.

Enthusiast Driver experiences quite a different situation. He is going 45 mph or 66 feet per second. Remember that basic physics indicates that there is 125% more energy involved because Enthusiast is cornering 50% faster. Remember also that the greater energy causes the outside springs to compress an additional 1-¼ inches. Assuming a "linear" suspension response time, it will take Enthusiastic 4.5 seconds of transition at each end of the turn. He spends 297 feet of transition during turn entry (66 feet per second x 4.5 seconds), has only 128 feet of steady-state cornering 297 feet of transition at the exit. This is why Enthusiast thinks the car is unresponsive. He is in the turn for a total of 10.9 seconds. Of these, he spends 9 seconds (82%) of the time in difficult transitional cornering and 1.9 seconds (18%) in relatively easy steady state cornering.

The technical name for this phenomenon is yaw response. The yaw response characteristic of a car is the single most important of that group of traits we call "handling". The parameters for determining an ideal yaw response characteristic are derived from study of the human nervous system. The yaw response must be designed to make the driver feel comfortable at the speed he wished to go. It cannot be too slow or too fast. It must be slow enough so the driver can react to steering inputs; yet, it must be fast enough so that corrections can be completed before an off-road excursion occurs. The "base-model coupe" has been designed by GM with an ideal yaw response for Joe Average, who normally corners at about 0.300 g. If a driver wants to corner at some higher speed, then the suspension must be modified to provide an ideal yaw response at the higher speed. In other words, we must keep the yaw time, when expressed as a percentage of total cornering time, constant. To keep Enthusiast Driver comfortable going around our typical turn at 45 mph, we must modify the suspension so about 18% of total cornering time is spent in transitional cornering. This is what keeping yaw time constant means.

The Indicators Game
At this point we should scrutinize the primary indicator of cornering performance – namely cornering force as expressed in g's. At the present time, we all tend to focus on how many g's a car can generate. We normally equate high g-forces with good handling. Does this equation really hold-up? Sometimes it does and sometimes it doesn't. We have all read comparison road tests where the car with the highest cornering force was also the slowest through a slalom course. This happens because g-forces are measured on a skid pad, which tests only steady state cornering. The skid pad tells nothing about yaw response characteristics during transitional cornering. Yet, it is these characteristics which are the most important factor contributing to superior handling.



Whether high cornering forces translate to superior handling or not depends on the honesty of the suspension designer. If he designs a complete system which takes into account both transient and steady-state cornering, then yes, high cornering forces will mean superior handling. However, if he uses tricks just to yield high cornering force numbers and does not do his homework on the remaining suspension components, the no, superior handling will not result. Remember, skid pad results are just indicators; the real test of good handling is how your car performs over your favorite back road, in transition as well as "steady-state".

How can we judge the honesty of the designer's work? A good place to start is by examining how General Motors upgrades a base-model coupe into either a Z-51 Corvette, Z-28 Camaro or Trans Am Firebird.

A Lesson from GM
It is a myth that General Motors cannot design good cars. Their engineers and technical staff are among the best in the world. If you have any doubts just look at GM's impressive competition record. It includes numerous successes doing both officially sponsored corporate projects as well as countless backdoor efforts. You may remember their NASCAR efforts of the 50's, the Grand Sport Corvette, and the racing Camaros of the late 60's. From our point of view, the only problem is that these superior technical capabilities are generally used to produce designs for the average buyer rather than the true enthusiast.

When these talented engineers redesign the base coupe into a Z-51 Corvette, Z-28 or Trans Am, they treat the whole car as an interrelated system. They make detail changes to a wide range of suspension components. The Z-51 Corvette, Z-28 or Trans Am differ from the base coupe in the hardness of rubber suspension bushings, the rate of both front and rear springs, the diameter of sway bars, the ratio and feel of the steering gear, the width of the wheels, and the size and compound of the tires. It takes the combined effect of all these changes to maintain a balanced car, which (1) exhibits cornering forces in the 0.800 ranges and (2) has good yaw response characteristics. Notice that they change several of the major system components and not just a single item such as a front or rear sway bar. The total system approach produces a car with an integrated, balanced feel derived from all the parts working in harmony.



The other thing to notice is that all of the revised parts are stiffer than the normal part. The springs are stiffer, the sway bars are stiffer and the rubber bushings are harder (which is another way of saying stiffer). As we discussed above, they must be stiffer to deal with the increased energy generated by higher cornering speeds.

No Free Lunch
We need to understand one final point. Every given set of suspension components has a limited working range. As suspension components are modified for higher cornering speeds, the working range becomes narrower. Thus, the base-model coupe rides well at slow speeds, corners satisfactorily up to about 0.450 g and is uncomfortable at 0.650 g (145%). The Z-28 or Trans Am has a firm ride, corners well to 0.720 g and becomes difficult to control at 0.770 g (107%). A good combination street/slalom car has a very firm ride, corners well to 0.875 g and feels "edgy" at 0.900 g (103%). The typical racecar has no ride comfort, corners well at 1.200 g, and leaves the road at 1.210 g (101%). Notice that as cars are tuned to handle well at higher g-forces, low speed ride comfort is sacrificed.

Under current technology, the twin goals of pillow-soft low-speed ride and superior yaw responses at high cornering forces cannot be accommodated in the same car. The truth is that tuning the suspension to work well at higher cornering speeds always trades off some low-speed ride comfort. We must each individually decide how much low-speed ride comfort should be sacrificed for added high-speed cornering capability. As a wise man once said, "There is no free lunch."

So there it is, the real "straight talk" about high-speed handling. You won't remember all the details but you should remember the following three points. First, superior high-speed handling is more than just high cornering power. It must include a balance of both high cornering power and correct yaw response characteristics. Second, a car with superior high-speed handling is produced only by the systematic modification of a wide range of suspension components. Just bolting on a sway bar or some other part won't get the job done. Finally, as cornering speeds get higher, the suspension system must get stiffer in order to handle the increased energy levels.

Author, Dick Guldstrand

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Tim's Valiant looks really interesting . Do you know what mods it has?

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Trying to remember. AndyF might know better.

1.24 T-bars
275/40/17 tires front/rear
17x9 rims front/rear
13" AREngineering Viper/Brembo caliper conversion
Firm Feel tubular UCA's
Bilstein shocks
I think rear drum brakes?
Roll cage with bars going into the engine compartment
Leaf rear springs, can't remember rate or brand
Front sway bar, can't remember size or brand. Might be a custom one adjustable one
Don't remember if he is running a rear sway bar
73-76 front K-member welded/reinforced
power steering

Just going off memory. Might be off on a few things. But you can see things are simple but very effective.

This is certainly one of the fastest pre 1980 street driven/legal Mopar/driver road race combinations with stock located suspension points and suspension type in the country. With the new bullet 426 small block motor that AndyF is building this is going to be near the top of any pre 1980 Mopar whether it has a kit car chassis under it or not.

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That is a pretty good list. Tim finally got around to swapping rear disc brakes onto the car. He used the DoctorDiff kit which is the best rear disc setup on the market.

He does have a small rear bar on the car. Rear springs are stockers. We're interested in the new Hotchkis rear leaf springs but haven't ever heard back from them so we might just stay with the factory original springs for next season.

The new 427 inch bullet is going together. Should be on the dyno sometime in Jan. Tim has an aluminum driveshaft for the car and Passion sent us some aluminum tranny stuff. New Baer rotors should drop 12 lbs of unsprung weight. Hughes Engines did the CNC port work on the heads and RyanJ is porting the intake. We got a killer new carb from Bo Laws.

It will be interesting to see how the '68 goes when it hits the track next spring. It will be lighter than before and will have a ton more power. Tim didn't have much trouble with Vipers or Vettes before so the new setup might be eye opening. A Z06 with a good driver would give Tim more than he could handle last year but I bet that situation will even up this next year. But you don't know until you get it on the track. It might take some time to sort out the cam profile with the tranny gear ratios and stuff like that.

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It's Just Human
Back at our typical turn, we can watch more closely as our two drivers negotiate the corner. Recall that Joe Average went around the turn at 30 mph, or to put it another way, at 4 feet per second.

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“Will an Alterkation make a muscle car handle like a vette?” I don’t know but this is what works for me and I can beat up most corvettes and other fast cars but not all. There are quality packages to make your car handle like that Tupperware [vette] but many of them are out of the common man’s realm. [$$$$$] I have not found anyone running an alterkation like I run my T bars. Since 1990 I have been regularly flogging an E body 4 speed around Watkins Glen Racetrack with Phoenix CMR driving School. The approach since day one has always been it’s a street car that gets driven on the road course. This has always been for fun and to make my car a better driving/handling street car-I think it’s called pro touring now…

Let’s do some math: average of 18 laps per session @ 3.4 miles per lap is 61.2 miles, 4 x a day is 244.8 miles a day for 2 days. 489.6 miles x19 years is 9302 miles. For 5 years I ran the Glen 2x yr so add 2448 miles. 11750 miles. I might know what’s working by now. As the years go by the car & I both have gotten faster and better. I have had some wonderful instructors in the passenger seat and I have been passenger doing HOT laps in cars like Ford GTs, SCCA mustangs, track mustangs, Z06 corvettes etc. In addition to seat time there is classroom instruction & a lot of post run discussion among us as well as helpful advice and the sharing of ideas. My fellow speed demons are always watching my car & lap times-go figure-they are always surprised at the go & whoa…and then again so am I.

I started with 15 inch rallye wheels with 235 60 15 BFG tires, KYB Shocks & stock disc/drum brakes with Velvetouch brake linings front & rear, stock sway bars, engine trans seats and seat belts etc. stock stock stock

In the process I learned the 4 most important items to have on your handling car are:
Sticky tires
Real seats & seat belts
Adjustable shocks
Brakes that don’t fade away
Everything after that improves on the basics.

Even the stock suspension set up was limited by the tire and shock choice and the overall handling [think lap times] was severely handicapped by not being held firmly in the seat by a 5 pt seat belt.

Let me show you where the money goes

Level Q Sub Zero AAR ‘Cuda as currently configured, the numbers are the $$$$

Tubular UCA urethane bushing RMS Chassis Components 250
Tubular adj strut rods w/rod ends RMS Chassis Components 199
Boxed lca with rubber pin bushing 50
Shocks QA1 adjustable… RMS 580
Springs 160 lbs/in ESPO 260
Urethane Spring bushings ESPO 40
Torsion Bars 1.120 Mopar 150
Sway Bars 1-1/8 front ¾ rear Firm Feel 500
adj front leaf spring hanger 3 position [lowers car] Mopax 100
11/16 Seamless Tie Rod sleeves Firm Feel 175
16:1 Manual Steering Flaming River 400
Brake upgrade: RMS
wilwood dynalyte calipers w/12 inch stock rotors, spindles 625
11 drum rear w/small wheel cyl and Velvetouch shoes 150
Bracing across entire pkge tray for seat belts and x braces reinforced for the:
Corbeau seats and 5 pt belts 1000
Front spoiler MAS 60
Passon Alum OD 4 sp 2799
3.55 sure grip
Synthetic lubricants
Driveshaft Denny’s 400
Accusump 400
Aluminum head six pak 416 Muscle Motors/Repine 400 rwhp 8000
MSD ignition 200
16x8 Alum wheels 1000
255-50ZR16 competition tire Toyo RA1 1000
Air ducts on the front rotors, no splash shields
Clutch 10.95 Custom “Emerald” by Rochester Clutch & Brake w/6 paddle Velvetouch disc 300
SFI flywheel 300
Good tach SW 275
Light Battery in trunk 200
Seat belts 250

Body flex-every year the car gets an inspection, every year there are no surprises. 11000 miles and counting…want to come and inspect yourself, pm me for an appointment. Nothing has broken, twisted or cracked & the doors, trunk & hood close as they always have. I do not beat the equipment and that makes a difference in the body stresses. Design me an X brace for the floor pan that fits like a glove as has been suggested here and I will install it and be faster than I am now. Smoooth is fast and you can only go so fast smoothly. No serious body stresses when smooth and it is such a blast to run up and down the gear box with your foot buried in the throttle. If you hate Miatas on your butt then make sure you have enough ponies for the straight-aways.

If you spend any time flogging the road course you will meet many a driver who gets the gleam in their eye as they talk about the car “rotating thru the turn”. When the car finally does “rotate” you have arrived. To get my po$ to “rotate” the 3 key items were seats, seatbelts, and TIRES more than anything else...Yes my car rotates and that is a treat!

Rear spring rates: Remember I have street car that runs the road course. I ran 115lb/inch 5 leaf springs that were not enough. I currently have installed ESPO 6 leaves that come in at 160 lbs/inch. I had to soften up the rear bar by using rubber sway bar bushings. I am thinking about removing the smallest leaf from each spring to reduce the rate slightly. Cost and availability was the reason I used the ESPO 6 leaves. I am not dissatisfied with the results so far but in hindsight I wish I had started with the 5 leaf instead of the 6 leaf as my first choice. I have a nice set of lightly used E body six leave springs for sale…

Shocks: KYB, Edelbrock and most others “porpoise” when hot. Nuff said. With every car being different there is no one size fits all so adjustable shocks are the only way to go. Konis are too stiff for my SOTP meter. Remember street car driven on the roadcourse.

Tires & wheels: 16x8 wheels with the same 255-50 ZR16 competition tires. I am not going to argue with anyone about other tire/wheel combinations as this is what works extremely well with out compromise and shoe horns.

Several years ago I helped prepared a common man’s 440+6 real Superbird for the Glen and the results were phenomenal. I am looking for the paperwork so I can post the hardware and costs. It was not expensive; the owner drives the bird a lot and loves the car.

BTW I can’t out run a Z06, an AC Cobra, a Ford GT or Tim Werner'68 Valiant but I make them work hard for the lead.

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WOW!!! The information on this site can be priceless. I know that I will never see or experience what you have personally accomplished. I am happy to learn from your experience. Thanks for putting things in perspective.

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Level Q Sub Zero AAR ‘Cuda as currently configured, the numbers are the $$$$

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Oh man, I gotta come up with some name for my setup. Hmmm, let me see…

Level Y Ultra Zero Formula S 340 Barracuda

Stock UCA offset rubber bushing Moog 7103 RMS $40
Stock strut rods w/rod poly bushings cut 3/16” $30
Boxed LCA homemade with 1” strap steel poly bushing $20
Front Shocks QA1 adjustable… Used swap meet $80
Springs 130 lbs/in OE 340 Formula S 40 years old $0
Urethane Spring bushings Energy $40
Torsion Bars 0.99 Mopar (1994 pricing) $109
Sway Bars 1-1/8 front ¾ rear Firm Feel –Used swap meet $35 ft, $25 rr
11/16 Tie Rod sleeves junk yard $8
Mopar Part Remanufactured Power Steering box $160 (1994 and a good deal even then)
La Carra steering wheel Cedar Rapids swap meet never used $20
Brake upgrade: Junk Yard rotors, spindle, UCA’s. $90
HD Police Semi Metallic Pad Pin type Des Moines Mopar swap meet from Jeff Dory $15/set
MP/Willwood adjustable proportioning valve $40
MP Aluminum 1 1/32” bore master $50
Master adapter 2 aluminum bars from Industrial Metals’ extra’s bin $6
10 drum parts store shoes
73-76 K-member $50
K-member welding/reinforcing by a buddy and I bought the metal $20
3.23 sure grip OE $0
Re-ringed 340, VJ w/hardened seats, $600
15x8 4.5” backspacing rallye rims made from used centers $320
245-50ZR15 $450 for first set. $200 for 200 mile used second set
Sun Pro cruddy tach $10 swap meet used
Toyota Celica GTS seats –used out of the paper for $60


The larger front spring rate made the biggest impact. Rebuilt steering box, offset UCA bushings for caster, steering wheel, semi bolstered seats were big driver impact. But none of those really give a big mechanical performance gain.

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Steve, I think Red Bull Racing is more like it for you

Sorry, I just had to, what with your threatening to drink some before SFSF.

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Threating?? All night thrashing on the car before Spring Fling Speed Festival or getting ready for a Spring Fling show I inhale that stuff. Actually I like the AMP energy drink in 16 oz cans.



I still have a 16oz radiator overflow can made from Energy drink and duct tape.

Here's a pic at 12:55am before SFSF07. I like to keep them handy on the fender. Double fist style.